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<h2><a name="SECTION0025330000000000000000"></a><a name="legacy-unit-tests"></a>
<br>
23.3.3 Re-using old test code
            
</h2>

<p>
Some users will find that they have existing test code that they would
like to run from <tt class="module">unittest</tt>, without converting every old test
function to a <tt class="class">TestCase</tt> subclass.

<p>
For this reason, <tt class="module">unittest</tt> provides a <tt class="class">FunctionTestCase</tt>
class.  This subclass of <tt class="class">TestCase</tt> can be used to wrap an existing
test function.  Set-up and tear-down functions can also be provided.

<p>
Given the following test function:

<p>
<div class="verbatim"><pre>
def testSomething():
    something = makeSomething()
    assert something.name is not None
    # ...
</pre></div>

<p>
one can create an equivalent test case instance as follows:

<p>
<div class="verbatim"><pre>
testcase = unittest.FunctionTestCase(testSomething)
</pre></div>

<p>
If there are additional set-up and tear-down methods that should be
called as part of the test case's operation, they can also be provided
like so:

<p>
<div class="verbatim"><pre>
testcase = unittest.FunctionTestCase(testSomething,
                                     setUp=makeSomethingDB,
                                     tearDown=deleteSomethingDB)
</pre></div>

<p>
To make migrating existing test suites easier, <tt class="module">unittest</tt>
supports tests raising <tt class="exception">AssertionError</tt> to indicate test failure.
However, it is recommended that you use the explicit
<tt class="method">TestCase.fail*()</tt> and <tt class="method">TestCase.assert*()</tt> methods instead,
as future versions of <tt class="module">unittest</tt> may treat <tt class="exception">AssertionError</tt>
differently.

<p>
<span class="note"><b class="label">Note:</b>
Even though <tt class="class">FunctionTestCase</tt> can be used to quickly convert
an existing test base over to a <tt class="module">unittest</tt>-based system, this
approach is not recommended.  Taking the time to set up proper
<tt class="class">TestCase</tt> subclasses will make future test refactorings infinitely
easier.</span>

<p>

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<span class="release-info">Release 2.5.1, documentation updated on 18th April, 2007.</span>
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